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Liang Y, Carrillo-Baltodano AM, Martín-Durán JM. Emerging trends in the study of spiralian larvae. Evol Dev 2024; 26:e12459. [PMID: 37787615 DOI: 10.1111/ede.12459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 09/11/2023] [Accepted: 09/13/2023] [Indexed: 10/04/2023]
Abstract
Many animals undergo indirect development, where their embryogenesis produces an intermediate life stage, or larva, that is often free-living and later metamorphoses into an adult. As their adult counterparts, larvae can have unique and diverse morphologies and occupy various ecological niches. Given their broad phylogenetic distribution, larvae have been central to hypotheses about animal evolution. However, the evolution of these intermediate forms and the developmental mechanisms diversifying animal life cycles are still debated. This review focuses on Spiralia, a large and diverse clade of bilaterally symmetrical animals with a fascinating array of larval forms, most notably the archetypical trochophore larva. We explore how classic research and modern advances have improved our understanding of spiralian larvae, their development, and evolution. Specifically, we examine three morphological features of spiralian larvae: the anterior neural system, the ciliary bands, and the posterior hyposphere. The combination of molecular and developmental evidence with modern high-throughput techniques, such as comparative genomics, single-cell transcriptomics, and epigenomics, is a promising strategy that will lead to new testable hypotheses about the mechanisms behind the evolution of larvae and life cycles in Spiralia and animals in general. We predict that the increasing number of available genomes for Spiralia and the optimization of genome-wide and single-cell approaches will unlock the study of many emerging spiralian taxa, transforming our views of the evolution of this animal group and their larvae.
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Affiliation(s)
- Yan Liang
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | | | - José M Martín-Durán
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
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2
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McNulty P, Wu R, Yamaguchi A, Heckscher ES, Haas A, Nwankpa A, Skanata MM, Gershow M. CRASH2p: Closed-loop Two Photon Imaging in Freely Moving Animals. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.22.595209. [PMID: 38826435 PMCID: PMC11142166 DOI: 10.1101/2024.05.22.595209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Direct measurement of neural activity in freely moving animals is essential for understanding how the brain controls and represents behaviors. Genetically encoded calcium indicators report neural activity as changes in fluorescence intensity, but brain motion confounds quantitative measurement of fluorescence. Translation, rotation, and deformation of the brain and the movements of intervening scattering or auto-fluorescent tissue all alter the amount of fluorescent light captured by a microscope. Compared to single-photon approaches, two photon microscopy is less sensitive to scattering and off-target fluorescence, but more sensitive to motion, and two photon imaging has always required anchoring the microscope to the brain. We developed a closed-loop resonant axial-scanning high-speed two photon (CRASH2p) microscope for real-time 3D motion correction in unrestrained animals, without implantation of reference markers. We complemented CRASH2p with a novel scanning strategy and a multistage registration pipeline. We performed volumetric ratiometrically corrected functional imaging in the CNS of freely moving Drosophila larvae and discovered previously unknown neural correlates of behavior.
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Affiliation(s)
- Paul McNulty
- Department of Physics,New York University, New York, USA
| | - Rui Wu
- Department of Physics,New York University, New York, USA
| | | | - Ellie S. Heckscher
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL
| | - Andrew Haas
- Department of Physics,New York University, New York, USA
| | | | | | - Marc Gershow
- Department of Physics,New York University, New York, USA
- Center for Neural Science,New York University, New York, USA
- Neuroscience Institute, New York University, New York, USA
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3
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Bondoc-Naumovitz KG, Laeverenz-Schlogelhofer H, Poon RN, Boggon AK, Bentley SA, Cortese D, Wan KY. Methods and Measures for Investigating Microscale Motility. Integr Comp Biol 2023; 63:1485-1508. [PMID: 37336589 PMCID: PMC10755196 DOI: 10.1093/icb/icad075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 05/31/2023] [Accepted: 06/06/2023] [Indexed: 06/21/2023] Open
Abstract
Motility is an essential factor for an organism's survival and diversification. With the advent of novel single-cell technologies, analytical frameworks, and theoretical methods, we can begin to probe the complex lives of microscopic motile organisms and answer the intertwining biological and physical questions of how these diverse lifeforms navigate their surroundings. Herein, we summarize the main mechanisms of microscale motility and give an overview of different experimental, analytical, and mathematical methods used to study them across different scales encompassing the molecular-, individual-, to population-level. We identify transferable techniques, pressing challenges, and future directions in the field. This review can serve as a starting point for researchers who are interested in exploring and quantifying the movements of organisms in the microscale world.
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Affiliation(s)
| | | | - Rebecca N Poon
- Living Systems Institute, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK
| | - Alexander K Boggon
- Living Systems Institute, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK
| | - Samuel A Bentley
- Living Systems Institute, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK
| | - Dario Cortese
- Living Systems Institute, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK
| | - Kirsty Y Wan
- Living Systems Institute, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK
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4
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Bastin BR, Meha SM, Khindurangala L, Schneider SQ. Cooption of regulatory modules for tektin paralogs during ciliary band formation in a marine annelid larva. Dev Biol 2023; 503:95-110. [PMID: 37557946 DOI: 10.1016/j.ydbio.2023.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 07/25/2023] [Accepted: 07/28/2023] [Indexed: 08/11/2023]
Abstract
Tektins are a highly conserved family of coiled-coil domain containing proteins known to play a role in structure, stability and function of cilia and flagella. Tektin proteins are thought to form filaments which run the length of the axoneme along the inner surface of the A tubule of each microtubule doublet. Phylogenetic analyses suggest that the tektin family arose via duplications from a single tektin gene in a unicellular organism giving rise to four and five tektin genes in bilaterians and in spiralians, respectively. Although tektins are found in most metazoans, little is known about their expression and function outside of a handful of model species. Here we present the first comprehensive study of tektin family gene expression in any animal system, in the spiralian annelid Platynereis dumerilii. This indirect developing species retains a full ancient spiralian complement of five tektin genes. We show that all five tektins are expressed almost exclusively in known ciliary structures following the expression of the motile cilia master regulator foxJ1. The three older bilaterian tektin-1, tektin-2, and tektin-4 genes, show a high degree of spatial and temporal co-regulation, while the spiralian specific tektin-3/5A and tektin-3/5B show a delay in onset of expression in every ciliary structure. In addition, tektin-3/5B transcripts show a restricted subcellular localization to the most apical region near the multiciliary arrays. The exact recapitulation of the sequence of expression and localization of the five tektins at different times during larval development indicates the cooption of a fixed regulatory and cellular program during the formation of each ciliary band and multiciliated cell type in this spiralian.
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Affiliation(s)
- Benjamin R Bastin
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA.
| | - Steffanie M Meha
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan.
| | - Lalith Khindurangala
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA.
| | - Stephan Q Schneider
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA; Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan.
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5
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Yamaguchi A, Wu R, McNulty P, Karagyozov D, Mihovilovic Skanata M, Gershow M. Multi-neuronal recording in unrestrained animals with all acousto-optic random-access line-scanning two-photon microscopy. Front Neurosci 2023; 17:1135457. [PMID: 37389365 PMCID: PMC10303936 DOI: 10.3389/fnins.2023.1135457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 05/18/2023] [Indexed: 07/01/2023] Open
Abstract
To understand how neural activity encodes and coordinates behavior, it is desirable to record multi-neuronal activity in freely behaving animals. Imaging in unrestrained animals is challenging, especially for those, like larval Drosophila melanogaster, whose brains are deformed by body motion. A previously demonstrated two-photon tracking microscope recorded from individual neurons in freely crawling Drosophila larvae but faced limits in multi-neuronal recording. Here we demonstrate a new tracking microscope using acousto-optic deflectors (AODs) and an acoustic GRIN lens (TAG lens) to achieve axially resonant 2D random access scanning, sampling along arbitrarily located axial lines at a line rate of 70 kHz. With a tracking latency of 0.1 ms, this microscope recorded activities of various neurons in moving larval Drosophila CNS and VNC including premotor neurons, bilateral visual interneurons, and descending command neurons. This technique can be applied to the existing two-photon microscope to allow for fast 3D tracking and scanning.
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Affiliation(s)
- Akihiro Yamaguchi
- Department of Physics, New York University, New York, NY, United States
| | - Rui Wu
- Department of Physics, New York University, New York, NY, United States
| | - Paul McNulty
- Department of Physics, New York University, New York, NY, United States
| | - Doycho Karagyozov
- Department of Physics, New York University, New York, NY, United States
| | | | - Marc Gershow
- Department of Physics, New York University, New York, NY, United States
- Center for Neural Science, New York University, New York, NY, United States
- Neuroscience Institute, New York University, New York, NY, United States
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6
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Alicea B, Gordon R, Parent J. Embodied cognitive morphogenesis as a route to intelligent systems. Interface Focus 2023; 13:20220067. [PMID: 37065267 PMCID: PMC10102728 DOI: 10.1098/rsfs.2022.0067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 01/20/2023] [Indexed: 04/18/2023] Open
Abstract
The embryological view of development is that coordinated gene expression, cellular physics and migration provides the basis for phenotypic complexity. This stands in contrast with the prevailing view of embodied cognition, which claims that informational feedback between organisms and their environment is key to the emergence of intelligent behaviours. We aim to unite these two perspectives as embodied cognitive morphogenesis, in which morphogenetic symmetry breaking produces specialized organismal subsystems which serve as a substrate for the emergence of autonomous behaviours. As embodied cognitive morphogenesis produces fluctuating phenotypic asymmetry and the emergence of information processing subsystems, we observe three distinct properties: acquisition, generativity and transformation. Using a generic organismal agent, such properties are captured through models such as tensegrity networks, differentiation trees and embodied hypernetworks, providing a means to identify the context of various symmetry-breaking events in developmental time. Related concepts that help us define this phenotype further include concepts such as modularity, homeostasis and 4E (embodied, enactive, embedded and extended) cognition. We conclude by considering these autonomous developmental systems as a process called connectogenesis, connecting various parts of the emerged phenotype into an approach useful for the analysis of organisms and the design of bioinspired computational agents.
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Affiliation(s)
- Bradly Alicea
- OpenWorm Foundation, Boston, MA, USA
- Orthogonal Research and Education Laboratory, Champaign-Urbana, IL, USA
| | - Richard Gordon
- Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI 48201, USA
| | - Jesse Parent
- Orthogonal Research and Education Laboratory, Champaign-Urbana, IL, USA
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7
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Zhu J, Boivin JC, Pang S, Xu CS, Lu Z, Saalfeld S, Hess HF, Ohyama T. Comparative connectomics and escape behavior in larvae of closely related Drosophila species. Curr Biol 2023:S0960-9822(23)00675-9. [PMID: 37285846 DOI: 10.1016/j.cub.2023.05.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 05/02/2023] [Accepted: 05/17/2023] [Indexed: 06/09/2023]
Abstract
Evolution has generated an enormous variety of morphological, physiological, and behavioral traits in animals. How do behaviors evolve in different directions in species equipped with similar neurons and molecular components? Here we adopted a comparative approach to investigate the similarities and differences of escape behaviors in response to noxious stimuli and their underlying neural circuits between closely related drosophilid species. Drosophilids show a wide range of escape behaviors in response to noxious cues, including escape crawling, stopping, head casting, and rolling. Here we find that D. santomea, compared with its close relative D. melanogaster, shows a higher probability of rolling in response to noxious stimulation. To assess whether this behavioral difference could be attributed to differences in neural circuitry, we generated focused ion beam-scanning electron microscope volumes of the ventral nerve cord of D. santomea to reconstruct the downstream partners of mdIV, a nociceptive sensory neuron in D. melanogaster. Along with partner interneurons of mdVI (including Basin-2, a multisensory integration neuron necessary for rolling) previously identified in D. melanogaster, we identified two additional partners of mdVI in D. santomea. Finally, we showed that joint activation of one of the partners (Basin-1) and a common partner (Basin-2) in D. melanogaster increased rolling probability, suggesting that the high rolling probability in D. santomea is mediated by the additional activation of Basin-1 by mdIV. These results provide a plausible mechanistic explanation for how closely related species exhibit quantitative differences in the likelihood of expressing the same behavior.
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Affiliation(s)
- Jiayi Zhu
- Department of Biology, McGill University, Docteur Penfield, Montreal, QC H3A 1B1, Canada; Integrated Program of Neuroscience, McGill University, Pine Avenue W., Montreal, QC H3A 1A1, Canada
| | - Jean-Christophe Boivin
- Department of Biology, McGill University, Docteur Penfield, Montreal, QC H3A 1B1, Canada; Integrated Program of Neuroscience, McGill University, Pine Avenue W., Montreal, QC H3A 1A1, Canada
| | - Song Pang
- Janelia Research Campus, Howard Hughes Medical Institute, Helix Drive, Ashburn, VA 20147, USA
| | - C Shan Xu
- Janelia Research Campus, Howard Hughes Medical Institute, Helix Drive, Ashburn, VA 20147, USA
| | - Zhiyuan Lu
- Janelia Research Campus, Howard Hughes Medical Institute, Helix Drive, Ashburn, VA 20147, USA
| | - Stephan Saalfeld
- Janelia Research Campus, Howard Hughes Medical Institute, Helix Drive, Ashburn, VA 20147, USA
| | - Harald F Hess
- Janelia Research Campus, Howard Hughes Medical Institute, Helix Drive, Ashburn, VA 20147, USA
| | - Tomoko Ohyama
- Department of Biology, McGill University, Docteur Penfield, Montreal, QC H3A 1B1, Canada; Alan Edwards Center for Research on Pain, McGill University, University Street, Montreal, QC H3A 2B4, Canada.
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8
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Recent advances in nanowire sensor assembly using laminar flow in open space. Trends Analyt Chem 2023. [DOI: 10.1016/j.trac.2023.116918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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9
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Jasek S, Verasztó C, Brodrick E, Shahidi R, Kazimiers T, Kerbl A, Jékely G. Desmosomal connectomics of all somatic muscles in an annelid larva. eLife 2022; 11:71231. [PMID: 36537659 PMCID: PMC9876572 DOI: 10.7554/elife.71231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Accepted: 12/07/2022] [Indexed: 12/24/2022] Open
Abstract
Cells form networks in animal tissues through synaptic, chemical, and adhesive links. Invertebrate muscle cells often connect to other cells through desmosomes, adhesive junctions anchored by intermediate filaments. To study desmosomal networks, we skeletonised 853 muscle cells and their desmosomal partners in volume electron microscopy data covering an entire larva of the annelid Platynereis. Muscle cells adhere to each other, to epithelial, glial, ciliated, and bristle-producing cells and to the basal lamina, forming a desmosomal connectome of over 2000 cells. The aciculae - chitin rods that form an endoskeleton in the segmental appendages - are highly connected hubs in this network. This agrees with the many degrees of freedom of their movement, as revealed by video microscopy. Mapping motoneuron synapses to the desmosomal connectome allowed us to infer the extent of tissue influenced by motoneurons. Our work shows how cellular-level maps of synaptic and adherent force networks can elucidate body mechanics.
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Affiliation(s)
- Sanja Jasek
- Living Systems Institute, University of ExeterExeterUnited Kingdom
| | - Csaba Verasztó
- Living Systems Institute, University of ExeterExeterUnited Kingdom
| | - Emelie Brodrick
- Living Systems Institute, University of ExeterExeterUnited Kingdom
| | - Réza Shahidi
- Living Systems Institute, University of ExeterExeterUnited Kingdom
| | - Tom Kazimiers
- Janelia Research CampusAshburnUnited States,kazmos GmbHDresdenGermany
| | - Alexandra Kerbl
- Living Systems Institute, University of ExeterExeterUnited Kingdom
| | - Gáspár Jékely
- Living Systems Institute, University of ExeterExeterUnited Kingdom
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10
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Özpolat BD, Randel N, Williams EA, Bezares-Calderón LA, Andreatta G, Balavoine G, Bertucci PY, Ferrier DEK, Gambi MC, Gazave E, Handberg-Thorsager M, Hardege J, Hird C, Hsieh YW, Hui J, Mutemi KN, Schneider SQ, Simakov O, Vergara HM, Vervoort M, Jékely G, Tessmar-Raible K, Raible F, Arendt D. The Nereid on the rise: Platynereis as a model system. EvoDevo 2021; 12:10. [PMID: 34579780 PMCID: PMC8477482 DOI: 10.1186/s13227-021-00180-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 08/20/2021] [Indexed: 01/02/2023] Open
Abstract
The Nereid Platynereis dumerilii (Audouin and Milne Edwards (Annales des Sciences Naturelles 1:195-269, 1833) is a marine annelid that belongs to the Nereididae, a family of errant polychaete worms. The Nereid shows a pelago-benthic life cycle: as a general characteristic for the superphylum of Lophotrochozoa/Spiralia, it has spirally cleaving embryos developing into swimming trochophore larvae. The larvae then metamorphose into benthic worms living in self-spun tubes on macroalgae. Platynereis is used as a model for genetics, regeneration, reproduction biology, development, evolution, chronobiology, neurobiology, ecology, ecotoxicology, and most recently also for connectomics and single-cell genomics. Research on the Nereid started with studies on eye development and spiralian embryogenesis in the nineteenth and early twentieth centuries. Transitioning into the molecular era, Platynereis research focused on posterior growth and regeneration, neuroendocrinology, circadian and lunar cycles, fertilization, and oocyte maturation. Other work covered segmentation, photoreceptors and other sensory cells, nephridia, and population dynamics. Most recently, the unique advantages of the Nereid young worm for whole-body volume electron microscopy and single-cell sequencing became apparent, enabling the tracing of all neurons in its rope-ladder-like central nervous system, and the construction of multimodal cellular atlases. Here, we provide an overview of current topics and methodologies for P. dumerilii, with the aim of stimulating further interest into our unique model and expanding the active and vibrant Platynereis community.
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Affiliation(s)
- B. Duygu Özpolat
- Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA 02543 USA
| | - Nadine Randel
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ UK
| | - Elizabeth A. Williams
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | | | - Gabriele Andreatta
- Max Perutz Labs, University of Vienna, Dr. Bohr-Gasse 9/4, 1030 Vienna, Austria
| | - Guillaume Balavoine
- Institut Jacques Monod, University of Paris/CNRS, 15 rue Hélène Brion, 75013 Paris, France
| | - Paola Y. Bertucci
- European Molecular Biology Laboratory, Developmental Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - David E. K. Ferrier
- Gatty Marine Laboratory, The Scottish Oceans Institute, University of St Andrews, East Sands, St Andrews, Fife, KY16 8LB UK
| | | | - Eve Gazave
- Institut Jacques Monod, University of Paris/CNRS, 15 rue Hélène Brion, 75013 Paris, France
| | - Mette Handberg-Thorsager
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Jörg Hardege
- Department of Biological & Marine Sciences, Hull University, Cottingham Road, Hull, HU67RX UK
| | - Cameron Hird
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, UK
| | - Yu-Wen Hsieh
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Jerome Hui
- School of Life Sciences, Simon F.S. Li Marine Science Laboratory, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Kevin Nzumbi Mutemi
- European Molecular Biology Laboratory, Developmental Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Stephan Q. Schneider
- Institute of Cellular and Organismic Biology, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang, Taipei, 11529 Taiwan
| | - Oleg Simakov
- Department for Neurosciences and Developmental Biology, University of Vienna, Vienna, Austria
| | - Hernando M. Vergara
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, Howland Street 25, London, W1T 4JG UK
| | - Michel Vervoort
- Institut Jacques Monod, University of Paris/CNRS, 15 rue Hélène Brion, 75013 Paris, France
| | - Gáspár Jékely
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, UK
| | | | - Florian Raible
- Max Perutz Labs, University of Vienna, Dr. Bohr-Gasse 9/4, 1030 Vienna, Austria
| | - Detlev Arendt
- European Molecular Biology Laboratory, Developmental Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
- Centre for Organismal Studies (COS), University of Heidelberg, 69120 Heidelberg, Germany
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11
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Whole-body integration of gene expression and single-cell morphology. Cell 2021; 184:4819-4837.e22. [PMID: 34380046 PMCID: PMC8445025 DOI: 10.1016/j.cell.2021.07.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 05/05/2021] [Accepted: 07/14/2021] [Indexed: 01/10/2023]
Abstract
Animal bodies are composed of cell types with unique expression programs that implement their distinct locations, shapes, structures, and functions. Based on these properties, cell types assemble into specific tissues and organs. To systematically explore the link between cell-type-specific gene expression and morphology, we registered an expression atlas to a whole-body electron microscopy volume of the nereid Platynereis dumerilii. Automated segmentation of cells and nuclei identifies major cell classes and establishes a link between gene activation, chromatin topography, and nuclear size. Clustering of segmented cells according to gene expression reveals spatially coherent tissues. In the brain, genetically defined groups of neurons match ganglionic nuclei with coherent projections. Besides interneurons, we uncover sensory-neurosecretory cells in the nereid mushroom bodies, which thus qualify as sensory organs. They furthermore resemble the vertebrate telencephalon by molecular anatomy. We provide an integrated browser as a Fiji plugin for remote exploration of all available multimodal datasets. A cellular atlas integrates gene expression and ultrastructure for an entire annelid Morphometry of all segmented cells, nuclei, and chromatin categorizes cell classes Molecular anatomy and projectome of head ganglionic nuclei and mushroom bodies An open-source browser for multimodal big image data exploration and analysis
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12
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Revilla-i-Domingo R, Rajan VBV, Waldherr M, Prohaczka G, Musset H, Orel L, Gerrard E, Smolka M, Stockinger A, Farlik M, Lucas RJ, Raible F, Tessmar-Raible K. Characterization of cephalic and non-cephalic sensory cell types provides insight into joint photo- and mechanoreceptor evolution. eLife 2021; 10:e66144. [PMID: 34350831 PMCID: PMC8367381 DOI: 10.7554/elife.66144] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 08/04/2021] [Indexed: 12/11/2022] Open
Abstract
Rhabdomeric opsins (r-opsins) are light sensors in cephalic eye photoreceptors, but also function in additional sensory organs. This has prompted questions on the evolutionary relationship of these cell types, and if ancient r-opsins were non-photosensory. A molecular profiling approach in the marine bristleworm Platynereis dumerilii revealed shared and distinct features of cephalic and non-cephalic r-opsin1-expressing cells. Non-cephalic cells possess a full set of phototransduction components, but also a mechanosensory signature. Prompted by the latter, we investigated Platynereis putative mechanotransducer and found that nompc and pkd2.1 co-expressed with r-opsin1 in TRE cells by HCR RNA-FISH. To further assess the role of r-Opsin1 in these cells, we studied its signaling properties and unraveled that r-Opsin1 is a Gαq-coupled blue light receptor. Profiling of cells from r-opsin1 mutants versus wild-types, and a comparison under different light conditions reveals that in the non-cephalic cells light - mediated by r-Opsin1 - adjusts the expression level of a calcium transporter relevant for auditory mechanosensation in vertebrates. We establish a deep-learning-based quantitative behavioral analysis for animal trunk movements and identify a light- and r-Opsin-1-dependent fine-tuning of the worm's undulatory movements in headless trunks, which are known to require mechanosensory feedback. Our results provide new data on peripheral cell types of likely light sensory/mechanosensory nature. These results point towards a concept in which such a multisensory cell type evolved to allow for fine-tuning of mechanosensation by light. This implies that light-independent mechanosensory roles of r-opsins may have evolved secondarily.
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Affiliation(s)
- Roger Revilla-i-Domingo
- Max Perutz Labs, University of Vienna, Vienna BioCenterViennaAustria
- Research Platform “Rhythms of Life”, University of Vienna, Vienna BioCenterViennaAustria
- Research Platform "Single-Cell Regulation of Stem Cells", University of Vienna, Vienna BioCenterViennaAustria
| | - Vinoth Babu Veedin Rajan
- Max Perutz Labs, University of Vienna, Vienna BioCenterViennaAustria
- Research Platform “Rhythms of Life”, University of Vienna, Vienna BioCenterViennaAustria
| | - Monika Waldherr
- Max Perutz Labs, University of Vienna, Vienna BioCenterViennaAustria
- Research Platform “Rhythms of Life”, University of Vienna, Vienna BioCenterViennaAustria
| | - Günther Prohaczka
- Max Perutz Labs, University of Vienna, Vienna BioCenterViennaAustria
- Research Platform “Rhythms of Life”, University of Vienna, Vienna BioCenterViennaAustria
| | - Hugo Musset
- Max Perutz Labs, University of Vienna, Vienna BioCenterViennaAustria
- Research Platform “Rhythms of Life”, University of Vienna, Vienna BioCenterViennaAustria
| | - Lukas Orel
- Max Perutz Labs, University of Vienna, Vienna BioCenterViennaAustria
- Research Platform “Rhythms of Life”, University of Vienna, Vienna BioCenterViennaAustria
| | - Elliot Gerrard
- Division of Neuroscience & Experimental Psychology, University of ManchesterManchesterUnited Kingdom
| | - Moritz Smolka
- Max Perutz Labs, University of Vienna, Vienna BioCenterViennaAustria
- Research Platform “Rhythms of Life”, University of Vienna, Vienna BioCenterViennaAustria
- Center for Integrative Bioinformatics Vienna, Max Perutz Labs, University of Vienna and Medical University of ViennaViennaAustria
| | - Alexander Stockinger
- Max Perutz Labs, University of Vienna, Vienna BioCenterViennaAustria
- Research Platform “Rhythms of Life”, University of Vienna, Vienna BioCenterViennaAustria
- Research Platform "Single-Cell Regulation of Stem Cells", University of Vienna, Vienna BioCenterViennaAustria
| | - Matthias Farlik
- CeMM Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
- Department of Dermatology, Medical University of ViennaViennaAustria
| | - Robert J Lucas
- Division of Neuroscience & Experimental Psychology, University of ManchesterManchesterUnited Kingdom
| | - Florian Raible
- Max Perutz Labs, University of Vienna, Vienna BioCenterViennaAustria
- Research Platform “Rhythms of Life”, University of Vienna, Vienna BioCenterViennaAustria
- Research Platform "Single-Cell Regulation of Stem Cells", University of Vienna, Vienna BioCenterViennaAustria
| | - Kristin Tessmar-Raible
- Max Perutz Labs, University of Vienna, Vienna BioCenterViennaAustria
- Research Platform “Rhythms of Life”, University of Vienna, Vienna BioCenterViennaAustria
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13
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Abstract
The evolutionary origin of the nervous system has been a matter of long-standing debate. This is due to the different perspectives taken. Earlier studies addressed nervous system origins at the cellular level. They focused on the selective advantage of the first neuron in its local context, and considered vertical sensory-motor reflex arcs the first nervous system. Later studies emphasized the value of the nervous system at the tissue level. Rather than acting locally, early neurons were seen as part of an elementary nerve net that enabled the horizontal coordination of tissue movements. Opinions have also differed on the nature of effector cells. While most authors have favoured contractile systems, others see the key output of the incipient nervous system in the coordination of motile cilia, or the secretion of antimicrobial peptides. I will discuss these divergent views and explore how they can be validated by molecular and single-cell data. From this survey, possible consensus emerges: (i) the first manifestation of the nervous system likely was a nerve net, whereas specialized local circuits evolved later; (ii) different nerve nets may have evolved for the coordination of contractile or cilia-driven movements; (iii) all evolving nerve nets facilitated new forms of animal behaviour with increasing body size. This article is part of the theme issue 'Basal cognition: multicellularity, neurons and the cognitive lens'.
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Affiliation(s)
- Detlev Arendt
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
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14
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Jékely G. The chemical brain hypothesis for the origin of nervous systems. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190761. [PMID: 33550946 PMCID: PMC7935135 DOI: 10.1098/rstb.2019.0761] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2020] [Indexed: 12/13/2022] Open
Abstract
In nervous systems, there are two main modes of transmission for the propagation of activity between cells. Synaptic transmission relies on close contact at chemical or electrical synapses while volume transmission is mediated by diffusible chemical signals and does not require direct contact. It is possible to wire complex neuronal networks by both chemical and synaptic transmission. Both types of networks are ubiquitous in nervous systems, leading to the question which of the two appeared first in evolution. This paper explores a scenario where chemically organized cellular networks appeared before synapses in evolution, a possibility supported by the presence of complex peptidergic signalling in all animals except sponges. Small peptides are ideally suited to link up cells into chemical networks. They have unlimited diversity, high diffusivity and high copy numbers derived from repetitive precursors. But chemical signalling is diffusion limited and becomes inefficient in larger bodies. To overcome this, peptidergic cells may have developed projections and formed synaptically connected networks tiling body surfaces and displaying synchronized activity with pulsatile peptide release. The advent of circulatory systems and neurohemal organs further reduced the constraint imposed on chemical signalling by diffusion. This could have contributed to the explosive radiation of peptidergic signalling systems in stem bilaterians. Neurosecretory centres in extant nervous systems are still predominantly chemically wired and coexist with the synaptic brain. This article is part of the theme issue 'Basal cognition: multicellularity, neurons and the cognitive lens'.
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Affiliation(s)
- Gáspár Jékely
- Living Systems Institute, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
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15
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Kuo DH, De-Miguel FF, Heath-Heckman EAC, Szczupak L, Todd K, Weisblat DA, Winchell CJ. A tale of two leeches: Toward the understanding of the evolution and development of behavioral neural circuits. Evol Dev 2020; 22:471-493. [PMID: 33226195 DOI: 10.1111/ede.12358] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 10/23/2020] [Accepted: 11/02/2020] [Indexed: 11/29/2022]
Abstract
In the animal kingdom, behavioral traits encompass a broad spectrum of biological phenotypes that have critical roles in adaptive evolution, but an EvoDevo approach has not been broadly used to study behavior evolution. Here, we propose that, by integrating two leech model systems, each of which has already attained some success in its respective field, it is possible to take on behavioral traits with an EvoDevo approach. We first identify the developmental changes that may theoretically lead to behavioral evolution and explain why an EvoDevo study of behavior is challenging. Next, we discuss the pros and cons of the two leech model species, Hirudo, a classic model for invertebrate neurobiology, and Helobdella, an emerging model for clitellate developmental biology, as models for behavioral EvoDevo research. Given the limitations of each leech system, neither is particularly strong for behavioral EvoDevo. However, the two leech systems are complementary in their technical accessibilities, and they do exhibit some behavioral similarities and differences. By studying them in parallel and together with additional leech species such as Haementeria, it is possible to explore the different levels of behavioral development and evolution.
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Affiliation(s)
- Dian-Han Kuo
- Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - Francisco F De-Miguel
- Instituto de Fisiología Celular - Neurociencias, Universidad Nacional Autónoma de México, México City, México
| | | | - Lidia Szczupak
- Departamento de Fisiología Biología Molecular y Celular, Universidad de Buenos Aires, and IFIBYNE UBA-CONICET, Buenos Aires, Argentina
| | - Krista Todd
- Department of Neuroscience, Westminster College, Salt Lake City, Utah, USA
| | - David A Weisblat
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Christopher J Winchell
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
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16
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Gintoli M, Mohanan S, Salter P, Williams E, Beard JD, Jekely G, Corbett AD. Spinning disk-remote focusing microscopy. BIOMEDICAL OPTICS EXPRESS 2020; 11:2874-2888. [PMID: 32637230 PMCID: PMC7316025 DOI: 10.1364/boe.389904] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/23/2020] [Accepted: 04/26/2020] [Indexed: 06/11/2023]
Abstract
Fast confocal imaging was achieved by combining remote focusing with differential spinning disk optical sectioning to rapidly acquire images of live samples at cellular resolution. Axial and lateral full width half maxima less than 5 µm and 490 nm respectively are demonstrated over 130 µm axial range with a 256 × 128 µm field of view. A water-index calibration slide was used to achieve an alignment that minimises image volume distortion. Application to live biological samples was demonstrated by acquiring image volumes over a 24 µm axial range at 1 volume/s, allowing for the detection of calcium-based neuronal activity in Platynereis dumerilii larvae.
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Affiliation(s)
- Michele Gintoli
- Department of Physics and Astronomy, University of Exeter, Exeter, EX4 4QL, UK
| | - Sharika Mohanan
- Department of Physics and Astronomy, University of Exeter, Exeter, EX4 4QL, UK
| | - Patrick Salter
- Department of Engineering Science, University of Oxford, Parks Road, Oxford, OX1 3PJ, UK
| | | | - James D. Beard
- Living Systems Institute, University of Exeter, Exeter, EX4 4QD, UK
| | - Gaspar Jekely
- Living Systems Institute, University of Exeter, Exeter, EX4 4QD, UK
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17
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Bjerre AS, Palmer LM. Probing Cortical Activity During Head-Fixed Behavior. Front Mol Neurosci 2020; 13:30. [PMID: 32180705 PMCID: PMC7059801 DOI: 10.3389/fnmol.2020.00030] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 02/10/2020] [Indexed: 01/20/2023] Open
Abstract
The cortex is crucial for many behaviors, ranging from sensory-based behaviors to working memory and social behaviors. To gain an in-depth understanding of the contribution to these behaviors, cellular and sub-cellular recordings from both individual and populations of cortical neurons are vital. However, techniques allowing such recordings, such as two-photon imaging and whole-cell electrophysiology, require absolute stability of the head, a requirement not often fulfilled in freely moving animals. Here, we review and compare behavioral paradigms that have been developed and adapted for the head-fixed preparation, which together offer the needed stability for live recordings of neural activity in behaving animals. We also review how the head-fixed preparation has been used to explore the function of primary sensory cortices, posterior parietal cortex (PPC) and anterior lateral motor (ALM) cortex in sensory-based behavioral tasks, while also discussing the considerations of performing such recordings. Overall, this review highlights the head-fixed preparation as allowing in-depth investigation into the neural activity underlying behaviors by providing highly controllable settings for precise stimuli presentation which can be combined with behavioral paradigms ranging from simple sensory detection tasks to complex, cross-modal, memory-guided decision-making tasks.
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Affiliation(s)
- Ann-Sofie Bjerre
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - Lucy M Palmer
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
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18
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Kuehn E, Stockinger AW, Girard J, Raible F, Özpolat BD. A scalable culturing system for the marine annelid Platynereis dumerilii. PLoS One 2019; 14:e0226156. [PMID: 31805142 PMCID: PMC6894799 DOI: 10.1371/journal.pone.0226156] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 11/20/2019] [Indexed: 12/16/2022] Open
Abstract
Platynereis dumerilii is a marine segmented worm (annelid) with externally fertilized embryos and it can be cultured for the full life cycle in the laboratory. The accessibility of embryos and larvae combined with the breadth of the established molecular and functional techniques has made P. dumerilii an attractive model for studying development, cell lineages, cell type evolution, reproduction, regeneration, the nervous system, and behavior. Traditionally, these worms have been kept in rooms dedicated for their culture. This allows for the regulation of temperature and light cycles, which is critical to synchronizing sexual maturation. However, regulating the conditions of a whole room has limitations, especially if experiments require being able to change culturing conditions. Here we present scalable and flexible culture methods that provide ability to control the environmental conditions, and have a multi-purpose culture space. We provide a closed setup shelving design with proper light conditions necessary for P. dumerilii to mature. We also implemented a standardized method of feeding P. dumerilii cultures with powdered spirulina which relieves the ambiguity associated with using frozen spinach, and helps standardize nutrition conditions across experiments and across different labs. By using these methods, we were able to raise mature P. dumerilii, capable of spawning and producing viable embryos for experimentation and replenishing culture populations. These methods will allow for the further accessibility of P. dumerilii as a model system, and they can be adapted for other aquatic organisms.
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Affiliation(s)
- Emily Kuehn
- Marine Biological Laboratory, Woods Hole, Massachusetts, United States of America
| | | | - Jerome Girard
- Marine Biological Laboratory, Woods Hole, Massachusetts, United States of America
| | | | - B. Duygu Özpolat
- Marine Biological Laboratory, Woods Hole, Massachusetts, United States of America
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19
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Constraining computational models using electron microscopy wiring diagrams. Curr Opin Neurobiol 2019; 58:94-100. [PMID: 31470252 DOI: 10.1016/j.conb.2019.07.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 07/25/2019] [Indexed: 12/18/2022]
Abstract
Numerous efforts to generate "connectomes," or synaptic wiring diagrams, of large neural circuits or entire nervous systems are currently underway. These efforts promise an abundance of data to guide theoretical models of neural computation and test their predictions. However, there is not yet a standard set of tools for incorporating the connectivity constraints that these datasets provide into the models typically studied in theoretical neuroscience. This article surveys recent approaches to building models with constrained wiring diagrams and the insights they have provided. It also describes challenges and the need for new techniques to scale these approaches to ever more complex datasets.
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20
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A Behavioral Assay to Study Effects of Retinoid Pharmacology on Nervous System Development in a Marine Annelid. Methods Mol Biol 2019. [PMID: 31359398 DOI: 10.1007/978-1-4939-9585-1_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Autonomous animal locomotion, such as swimming, is modulated by neuronal networks acting on cilia or muscles. Understanding how these networks are formed and coordinated is a complex scientific problem, which requires various technical approaches. Among others, behavioral studies of developing animals treated with exogenous substances have proven to be a successful approach for studying the functions of neuronal networks. One such substance crucial for the proper development of the nervous system is the vitamin A-derived morphogen retinoic acid (RA). In the larva of the marine annelid Platynereis dumerilii , for example, RA is involved in the specification and differentiation of individual neurons and responsible for orchestrating the swimming behavior of the developing larva. Here, we report a workflow to analyze the effects of RA on the locomotion of the P. dumerilii larva. We provide a protocol for both the treatment with RA and the recording of larval swimming behavior. Additionally, we present a pipeline for the analysis of the obtained data in terms of swimming speed and movement trajectory. This chapter thus summarizes the methodology for analyzing the effects of a specific drug treatment on larval swimming behavior. We expect this approach to be readily adaptable to a wide variety of pharmacological compounds and aquatic species.
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21
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Abstract
The brain's synaptic networks endow an animal with powerfully adaptive biological behavior. Maps of such synaptic circuits densely reconstructed in those model brains that can be examined and manipulated by genetic means offer the best prospect for understanding the underlying biological bases of behavior. That prospect is now technologically feasible and a scientifically enabling possibility in neurobiology, much as genomics has been in molecular biology and genetics. In Drosophila, two major advances are in electron microscopic technology, using focused ion beam-scanning electron microscopy (FIB-SEM) milling to capture and align digital images, and in computer-aided reconstruction of neuron morphologies. The last decade has witnessed enormous progress in detailed knowledge of the actual synaptic circuits formed by real neurons. Advances in various brain regions that heralded identification of the motion-sensing circuits in the optic lobe are now extending to other brain regions, with the prospect of encompassing the fly's entire nervous system, both brain and ventral nerve cord.
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Affiliation(s)
- Louis K Scheffer
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147-2408, USA;
| | - Ian A Meinertzhagen
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147-2408, USA; .,Department of Psychology and Neuroscience and Department of Biology, Life Sciences Centre, Dalhousie University, Halifax, Canada B3H 4R2
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22
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Whole-animal connectomes of both Caenorhabditis elegans sexes. Nature 2019; 571:63-71. [PMID: 31270481 DOI: 10.1038/s41586-019-1352-7] [Citation(s) in RCA: 370] [Impact Index Per Article: 74.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 05/28/2019] [Indexed: 01/08/2023]
Abstract
Knowledge of connectivity in the nervous system is essential to understanding its function. Here we describe connectomes for both adult sexes of the nematode Caenorhabditis elegans, an important model organism for neuroscience research. We present quantitative connectivity matrices that encompass all connections from sensory input to end-organ output across the entire animal, information that is necessary to model behaviour. Serial electron microscopy reconstructions that are based on the analysis of both new and previously published electron micrographs update previous results and include data on the male head. The nervous system differs between sexes at multiple levels. Several sex-shared neurons that function in circuits for sexual behaviour are sexually dimorphic in structure and connectivity. Inputs from sex-specific circuitry to central circuitry reveal points at which sexual and non-sexual pathways converge. In sex-shared central pathways, a substantial number of connections differ in strength between the sexes. Quantitative connectomes that include all connections serve as the basis for understanding how complex, adaptive behavior is generated.
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23
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Katz PS, Quinlan PD. The importance of identified neurons in gastropod molluscs to neuroscience. Curr Opin Neurobiol 2019; 56:1-7. [PMID: 30390485 DOI: 10.1016/j.conb.2018.10.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 10/08/2018] [Indexed: 01/10/2023]
Abstract
Gastropod molluscs have large neurons that are uniquely identifiable across individuals and across species based on neuroanatomical and neurochemical criteria, facilitating research into neural signaling and neural circuits. Novel neuropeptides have been identified through RNA sequencing and mass spectroscopic analysis of single neurons. The roles of peptides and other signaling molecules including second messengers have been placed in the context of small circuits that control simple behaviors. Despite the stereotypy, neurons vary over time in their activity in large ensembles. Furthermore, there is both intra-species and inter-species variation in synaptic properties and gene expression. Research on gastropod identified neurons highlights the features that might be expected to be stable in more complex systems when trying to identify cell types.
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Affiliation(s)
- Paul S Katz
- Neuroscience and Behavior Graduate Program, Department of Biology, University of Massachusetts Amherst, 611 North Pleasant Street, 221 Morrill Science Center 3, Amherst, MA 01003, United States.
| | - Phoenix D Quinlan
- Neuroscience and Behavior Graduate Program, Department of Biology, University of Massachusetts Amherst, 611 North Pleasant Street, 221 Morrill Science Center 3, Amherst, MA 01003, United States
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24
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Williams EA, Jékely G. Neuronal cell types in the annelid Platynereis dumerilii. Curr Opin Neurobiol 2019; 56:106-116. [DOI: 10.1016/j.conb.2018.12.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Revised: 12/14/2018] [Accepted: 12/17/2018] [Indexed: 02/08/2023]
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25
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Kourakis MJ, Borba C, Zhang A, Newman-Smith E, Salas P, Manjunath B, Smith WC. Parallel visual circuitry in a basal chordate. eLife 2019; 8:44753. [PMID: 30998184 PMCID: PMC6499539 DOI: 10.7554/elife.44753] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 04/11/2019] [Indexed: 12/28/2022] Open
Abstract
A common CNS architecture is observed in all chordates, from vertebrates to basal chordates like the ascidian Ciona. Ciona stands apart among chordates in having a complete larval connectome. Starting with visuomotor circuits predicted by the Ciona connectome, we used expression maps of neurotransmitter use with behavioral assays to identify two parallel visuomotor circuits that are responsive to different components of visual stimuli. The first circuit is characterized by glutamatergic photoreceptors and responds to the direction of light. These photoreceptors project to cholinergic motor neurons, via two tiers of cholinergic interneurons. The second circuit responds to changes in ambient light and mediates an escape response. This circuit uses GABAergic photoreceptors which project to GABAergic interneurons, and then to cholinergic interneurons. Our observations on the behavior of larvae either treated with a GABA receptor antagonist or carrying a mutation that eliminates photoreceptors indicate the second circuit is disinhibitory.
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Affiliation(s)
- Matthew J Kourakis
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
| | - Cezar Borba
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States
| | - Angela Zhang
- Department of Electrical and Computer Engineering, University of California, Santa Barbara, Santa Barbara, United States
| | - Erin Newman-Smith
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States.,Department of Molecular, Cell and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States
| | - Priscilla Salas
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States
| | - B Manjunath
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States
| | - William C Smith
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, United States.,Department of Molecular, Cell and Developmental Biology, University of California, Santa Barbara, Santa Barbara, United States
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26
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Bernardo-Garcia FJ, Syed M, Jékely G, Sprecher SG. Glass confers rhabdomeric photoreceptor identity in Drosophila, but not across all metazoans. EvoDevo 2019; 10:4. [PMID: 30873275 PMCID: PMC6399963 DOI: 10.1186/s13227-019-0117-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 02/15/2019] [Indexed: 12/14/2022] Open
Abstract
Across metazoans, visual systems employ different types of photoreceptor neurons (PRs) to detect light. These include rhabdomeric PRs, which exist in distantly related phyla and possess an evolutionarily conserved phototransduction cascade. While the development of rhabdomeric PRs has been thoroughly studied in the fruit fly Drosophila melanogaster, we still know very little about how they form in other species. To investigate this question, we tested whether the transcription factor Glass, which is crucial for instructing rhabdomeric PR formation in Drosophila, may play a similar role in other metazoans. Glass homologues exist throughout the animal kingdom, indicating that this protein evolved prior to the metazoan radiation. Interestingly, our work indicates that glass is not expressed in rhabdomeric photoreceptors in the planarian Schmidtea mediterranea nor in the annelid Platynereis dumerilii. Combined with a comparative analysis of the Glass DNA-binding domain, our data suggest that the fate of rhabdomeric PRs is controlled by Glass-dependent and Glass-independent mechanisms in different animal clades.
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Affiliation(s)
- F Javier Bernardo-Garcia
- 1Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland.,2Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158 USA
| | - Maryam Syed
- 1Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland
| | - Gáspár Jékely
- 3Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD UK
| | - Simon G Sprecher
- 1Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland
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27
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Miller CT, Hale ME, Okano H, Okabe S, Mitra P. Comparative Principles for Next-Generation Neuroscience. Front Behav Neurosci 2019; 13:12. [PMID: 30787871 PMCID: PMC6373779 DOI: 10.3389/fnbeh.2019.00012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 01/15/2019] [Indexed: 01/10/2023] Open
Abstract
Neuroscience is enjoying a renaissance of discovery due in large part to the implementation of next-generation molecular technologies. The advent of genetically encoded tools has complemented existing methods and provided researchers the opportunity to examine the nervous system with unprecedented precision and to reveal facets of neural function at multiple scales. The weight of these discoveries, however, has been technique-driven from a small number of species amenable to the most advanced gene-editing technologies. To deepen interpretation and build on these breakthroughs, an understanding of nervous system evolution and diversity are critical. Evolutionary change integrates advantageous variants of features into lineages, but is also constrained by pre-existing organization and function. Ultimately, each species’ neural architecture comprises both properties that are species-specific and those that are retained and shared. Understanding the evolutionary history of a nervous system provides interpretive power when examining relationships between brain structure and function. The exceptional diversity of nervous systems and their unique or unusual features can also be leveraged to advance research by providing opportunities to ask new questions and interpret findings that are not accessible in individual species. As new genetic and molecular technologies are added to the experimental toolkits utilized in diverse taxa, the field is at a key juncture to revisit the significance of evolutionary and comparative approaches for next-generation neuroscience as a foundational framework for understanding fundamental principles of neural function.
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Affiliation(s)
- Cory T Miller
- Cortical Systems and Behavior Laboratory, Neurosciences Graduate Program, University of California, San Diego, San Diego, CA, United States
| | - Melina E Hale
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL, United States
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine, Tokyo, Japan.,Laboratory for Marmoset Neural Architecture, RIKEN Center for Brain Science (CBS), Wako, Japan
| | - Shigeo Okabe
- Department of Cellular Neurobiology, Graduate School of Medicine and Faculty of Medicine, University of Tokyo, Tokyo, Japan
| | - Partha Mitra
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, United States
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28
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Bezares-Calderón LA, Berger J, Jasek S, Verasztó C, Mendes S, Gühmann M, Almeda R, Shahidi R, Jékely G. Neural circuitry of a polycystin-mediated hydrodynamic startle response for predator avoidance. eLife 2018; 7:36262. [PMID: 30547885 PMCID: PMC6294549 DOI: 10.7554/elife.36262] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 11/16/2018] [Indexed: 12/19/2022] Open
Abstract
Startle responses triggered by aversive stimuli including predators are widespread across animals. These coordinated whole-body actions require the rapid and simultaneous activation of a large number of muscles. Here we study a startle response in a planktonic larva to understand the whole-body circuit implementation of the behaviour. Upon encountering water vibrations, larvae of the annelid Platynereis close their locomotor cilia and simultaneously raise the parapodia. The response is mediated by collar receptor neurons expressing the polycystins PKD1-1 and PKD2-1. CRISPR-generated PKD1-1 and PKD2-1 mutant larvae do not startle and fall prey to a copepod predator at a higher rate. Reconstruction of the whole-body connectome of the collar-receptor-cell circuitry revealed converging feedforward circuits to the ciliary bands and muscles. The wiring diagram suggests circuit mechanisms for the intersegmental and left-right coordination of the response. Our results reveal how polycystin-mediated mechanosensation can trigger a coordinated whole-body effector response involved in predator avoidance.
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Affiliation(s)
- Luis A Bezares-Calderón
- Living Systems Institute, University of Exeter, Exeter, United Kingdom.,Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Jürgen Berger
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Sanja Jasek
- Living Systems Institute, University of Exeter, Exeter, United Kingdom.,Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Csaba Verasztó
- Living Systems Institute, University of Exeter, Exeter, United Kingdom.,Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Sara Mendes
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Martin Gühmann
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Rodrigo Almeda
- Centre for Ocean Life, Technical University of Denmark, Denmark, Kingdom of Denmark
| | - Réza Shahidi
- Living Systems Institute, University of Exeter, Exeter, United Kingdom.,Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Gáspár Jékely
- Living Systems Institute, University of Exeter, Exeter, United Kingdom.,Max Planck Institute for Developmental Biology, Tübingen, Germany
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29
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Mulcahy B, Witvliet D, Holmyard D, Mitchell J, Chisholm AD, Meirovitch Y, Samuel ADT, Zhen M. A Pipeline for Volume Electron Microscopy of the Caenorhabditis elegans Nervous System. Front Neural Circuits 2018; 12:94. [PMID: 30524248 PMCID: PMC6262311 DOI: 10.3389/fncir.2018.00094] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 10/08/2018] [Indexed: 01/01/2023] Open
Abstract
The “connectome,” a comprehensive wiring diagram of synaptic connectivity, is achieved through volume electron microscopy (vEM) analysis of an entire nervous system and all associated non-neuronal tissues. White et al. (1986) pioneered the fully manual reconstruction of a connectome using Caenorhabditis elegans. Recent advances in vEM allow mapping new C. elegans connectomes with increased throughput, and reduced subjectivity. Current vEM studies aim to not only fill the remaining gaps in the original connectome, but also address fundamental questions including how the connectome changes during development, the nature of individuality, sexual dimorphism, and how genetic and environmental factors regulate connectivity. Here we describe our current vEM pipeline and projected improvements for the study of the C. elegans nervous system and beyond.
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Affiliation(s)
- Ben Mulcahy
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Daniel Witvliet
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Douglas Holmyard
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, ON, Canada.,Nanoscale Biomedical Imaging Facility, The Hospital for Sick Children, Peter Gilgan Centre for Research and Learning, Toronto, ON, Canada
| | - James Mitchell
- Center for Brain Science, Department of Physics, Harvard University, Cambridge, MA, United States
| | - Andrew D Chisholm
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Yaron Meirovitch
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Aravinthan D T Samuel
- Center for Brain Science, Department of Physics, Harvard University, Cambridge, MA, United States
| | - Mei Zhen
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
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30
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Pipkin JE, Bushong EA, Ellisman MH, Kristan Jr. WB. Verifying, Challenging, and Discovering New Synapses Among Fully EM-Reconstructed Neurons in the Leech Ganglion. Front Neuroanat 2018; 12:95. [PMID: 30487738 PMCID: PMC6246621 DOI: 10.3389/fnana.2018.00095] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 10/18/2018] [Indexed: 12/14/2022] Open
Abstract
Neural circuits underpin the production of animal behavior, largely based upon the precise pattern of synaptic connectivity among the neurons involved. For large numbers of neurons, determining such "connectomes" by direct physiological means is difficult, as physiological accessibility is ultimately required to verify and characterize the function of synapses. We collected a volume of images spanning an entire ganglion of the juvenile leech nervous system via serial blockface electron microscopy (SBEM). We validated this approach by reconstructing a well-characterized circuit of motor neurons involved in the swimming behavior of the leech by locating the synapses among them. We confirm that there are multiple synaptic contacts between connected pairs of neurons in the leech, and that these synapses are widely distributed across the region of neuropil in which the neurons' arbors overlap. We verified the anatomical existence of connections that had been described physiologically among longitudinal muscle motor neurons. We also found that some physiological connections were not present anatomically. We then drew upon the SBEM dataset to design additional physiological experiments. We reconstructed an uncharacterized neuron and one of its presynaptic partners identified from the SBEM dataset. We subsequently interrogated this cell pair via intracellular electrophysiology in an adult ganglion and found that the anatomically-discovered synapse was also functional physiologically. Our findings demonstrate the value of combining a connectomics approach with electrophysiology in the leech nervous system.
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Affiliation(s)
- Jason E. Pipkin
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Eric Allen Bushong
- National Center for Microscopy and Imaging Research, University of California, San Diego, La Jolla, CA, United States
| | - Mark H. Ellisman
- National Center for Microscopy and Imaging Research, University of California, San Diego, La Jolla, CA, United States
- Department of Neuroscience, University of California, San Diego, La Jolla, CA, United States
| | - William B. Kristan Jr.
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA, United States
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31
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Chartier TF, Deschamps J, Dürichen W, Jékely G, Arendt D. Whole-head recording of chemosensory activity in the marine annelid Platynereis dumerilii. Open Biol 2018; 8:180139. [PMID: 30381362 PMCID: PMC6223215 DOI: 10.1098/rsob.180139] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 10/08/2018] [Indexed: 01/13/2023] Open
Abstract
Chemical detection is key to various behaviours in both marine and terrestrial animals. Marine species, though highly diverse, have been underrepresented so far in studies on chemosensory systems, and our knowledge mostly concerns the detection of airborne cues. A broader comparative approach is therefore desirable. Marine annelid worms with their rich behavioural repertoire represent attractive models for chemosensation. Here, we study the marine worm Platynereis dumerilii to provide the first comprehensive investigation of head chemosensory organ physiology in an annelid. By combining microfluidics and calcium imaging, we record neuronal activity in the entire head of early juveniles upon chemical stimulation. We find that Platynereis uses four types of organs to detect stimuli such as alcohols, esters, amino acids and sugars. Antennae are the main chemosensory organs, compared to the more differentially responding nuchal organs or palps. We report chemically evoked activity in possible downstream brain regions including the mushroom bodies (MBs), which are anatomically and molecularly similar to insect MBs. We conclude that chemosensation is a major sensory modality for marine annelids and propose early Platynereis juveniles as a model to study annelid chemosensory systems.
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Affiliation(s)
- Thomas F Chartier
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Joran Deschamps
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Wiebke Dürichen
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Gáspár Jékely
- Living Systems Institute, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Detlev Arendt
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
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32
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Karagyozov D, Mihovilovic Skanata M, Lesar A, Gershow M. Recording Neural Activity in Unrestrained Animals with Three-Dimensional Tracking Two-Photon Microscopy. Cell Rep 2018; 25:1371-1383.e10. [PMID: 30380425 PMCID: PMC6287944 DOI: 10.1016/j.celrep.2018.10.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 08/07/2018] [Accepted: 10/02/2018] [Indexed: 11/25/2022] Open
Abstract
Optical recordings of neural activity in behaving animals can reveal the neural correlates of decision making, but brain motion, which often accompanies behavior, compromises these measurements. Two-photon point-scanning microscopy is especially sensitive to motion artifacts, and two-photon recording of activity has required rigid coupling between the brain and microscope. We developed a two-photon tracking microscope with extremely low-latency (360 μs) feedback implemented in hardware. This microscope can maintain continuous focus on neurons moving with velocities of 3 mm/s and accelerations of 1 m/s2 both in-plane and axially. We recorded calcium dynamics of motor neurons and inter-neurons in unrestrained freely behaving fruit fly larvae, correlating neural activity with stimulus presentations and behavioral outputs, and we measured light-induced depolarization of a visual interneuron in a moving animal using a genetically encoded voltage indicator. Our technique can be extended to stabilize recordings in a variety of moving substrates.
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Affiliation(s)
| | | | - Amanda Lesar
- Department of Physics, New York University, New York, NY, USA
| | - Marc Gershow
- Department of Physics, New York University, New York, NY, USA; Center for Neural Science, New York University, New York, NY, USA; Neuroscience Institute, New York University, New York, NY, USA.
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33
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Chou HC, Acevedo-Luna N, Kuhlman JA, Schneider SQ. PdumBase: a transcriptome database and research tool for Platynereis dumerilii and early development of other metazoans. BMC Genomics 2018; 19:618. [PMID: 30115014 PMCID: PMC6097317 DOI: 10.1186/s12864-018-4987-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 07/31/2018] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND The marine polychaete annelid Platynereis dumerilii has recently emerged as a prominent organism for the study of development, evolution, stem cells, regeneration, marine ecology, chronobiology and neurobiology within metazoans. Its phylogenetic position within the spiralian/ lophotrochozoan clade, the comparatively high conservation of ancestral features in the Platynereis genome, and experimental access to any stage within its life cycle, make Platynereis an important model for elucidating the complex regulatory and functional molecular mechanisms governing early development, later organogenesis, and various features of its larval and adult life. High resolution RNA-seq gene expression data obtained from specific developmental stages can be used to dissect early developmental mechanisms. However, the potential for discovery of these mechanisms relies on tools to search, retrieve, and compare genome-wide information within Platynereis, and across other metazoan taxa. RESULTS To facilitate exploration and discovery by the broader scientific community, we have developed a web-based, searchable online research tool, PdumBase, featuring the first comprehensive transcriptome database for Platynereis dumerilii during early stages of development (2 h ~ 14 h). Our database also includes additional stages over the P. dumerilii life cycle and provides access to the expression data of 17,213 genes (31,806 transcripts) along with annotation information sourced from Swiss-Prot, Gene Ontology, KEGG pathways, Pfam domains, TmHMM, SingleP, and EggNOG orthology. Expression data for each gene includes the stage, the normalized FPKM, the raw read counts, and information that can be leveraged for statistical analyses of differential gene expression and the construction of genome-wide co-expression networks. In addition, PdumBase offers early stage transcriptome expression data from five further species as a valuable resource for investigators interested in comparing early development in different organisms. To understand conservation of Platynereis gene models and to validate gene annotation, most Platynereis gene models include a comprehensive phylogenetic analysis across 18 species representing diverse metazoan taxa. CONCLUSIONS PdumBase represents the first online resource for the early developmental transcriptome of Platynereis dumerilii. It serves as a research platform for discovery and exploration of gene expression during early stages, throughout the Platynereis life cycle, and enables comparison to other model organisms. PdumBase is freely available at http://pdumbase.gdcb.iastate.edu .
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Affiliation(s)
- Hsien-Chao Chou
- Department of Genetics, Developmental and Cell Biology, Iowa State University, 503 Science Hall II, Ames, IA 50011 USA
- Present address: Center for Cancer Research, National Institutes of Health, Rockville, MD 20894 USA
| | - Natalia Acevedo-Luna
- Department of Genetics, Developmental and Cell Biology, Iowa State University, 503 Science Hall II, Ames, IA 50011 USA
| | - Julie A. Kuhlman
- Department of Genetics, Developmental and Cell Biology, Iowa State University, 503 Science Hall II, Ames, IA 50011 USA
| | - Stephan Q. Schneider
- Department of Genetics, Developmental and Cell Biology, Iowa State University, 503 Science Hall II, Ames, IA 50011 USA
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34
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Verasztó C, Gühmann M, Jia H, Rajan VBV, Bezares-Calderón LA, Piñeiro-Lopez C, Randel N, Shahidi R, Michiels NK, Yokoyama S, Tessmar-Raible K, Jékely G. Ciliary and rhabdomeric photoreceptor-cell circuits form a spectral depth gauge in marine zooplankton. eLife 2018; 7:36440. [PMID: 29809157 PMCID: PMC6019069 DOI: 10.7554/elife.36440] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 05/28/2018] [Indexed: 02/02/2023] Open
Abstract
Ciliary and rhabdomeric photoreceptor cells represent two main lines of photoreceptor-cell evolution in animals. The two cell types coexist in some animals, however how these cells functionally integrate is unknown. We used connectomics to map synaptic paths between ciliary and rhabdomeric photoreceptors in the planktonic larva of the annelid Platynereis and found that ciliary photoreceptors are presynaptic to the rhabdomeric circuit. The behaviors mediated by the ciliary and rhabdomeric cells also interact hierarchically. The ciliary photoreceptors are UV-sensitive and mediate downward swimming in non-directional UV light, a behavior absent in ciliary-opsin knockout larvae. UV avoidance overrides positive phototaxis mediated by the rhabdomeric eyes such that vertical swimming direction is determined by the ratio of blue/UV light. Since this ratio increases with depth, Platynereis larvae may use it as a depth gauge during vertical migration. Our results revealed a functional integration of ciliary and rhabdomeric photoreceptor cells in a zooplankton larva.
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Affiliation(s)
- Csaba Verasztó
- Max Planck Institute for Developmental Biology, Tübingen, Germany.,Living Systems Institute, University of Exeter, Exeter, United Kingdom
| | - Martin Gühmann
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Huiyong Jia
- Department of Biology, Emory University, Atlanta, United States
| | | | - Luis A Bezares-Calderón
- Max Planck Institute for Developmental Biology, Tübingen, Germany.,Living Systems Institute, University of Exeter, Exeter, United Kingdom
| | | | - Nadine Randel
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Réza Shahidi
- Max Planck Institute for Developmental Biology, Tübingen, Germany.,Living Systems Institute, University of Exeter, Exeter, United Kingdom
| | - Nico K Michiels
- Department of Biology, University of Tübingen, Tübingen, Germany
| | - Shozo Yokoyama
- Department of Biology, Emory University, Atlanta, United States
| | | | - Gáspár Jékely
- Max Planck Institute for Developmental Biology, Tübingen, Germany.,Living Systems Institute, University of Exeter, Exeter, United Kingdom
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35
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Abstract
In general, neurons in insects and many other invertebrate groups are individually recognizable, enabling us to assign an index number to specific neurons in a manner which is rarely possible in a vertebrate brain. This endows many studies on insect nervous systems with the opportunity to document neurons with great precision, so that in favourable cases we can return to the same neuron or neuron type repeatedly so as to recognize many separate morphological classes. The visual system of the fly's compound eye particularly provides clear examples of the accuracy of neuron wiring, allowing numerical comparisons between representatives of the same cell type, and estimates of the accuracy of their wiring.
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Affiliation(s)
- Ian A Meinertzhagen
- a Department of Psychology and Neuroscience , Life Sciences Centre, Dalhousie University , Halifax , Canada.,b Janelia Research Campus of Howard Hughes Medical Institute , Ashburn , VA , USA
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36
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Whole-organism cellular gene-expression atlas reveals conserved cell types in the ventral nerve cord of Platynereis dumerilii. Proc Natl Acad Sci U S A 2018; 114:5878-5885. [PMID: 28584082 DOI: 10.1073/pnas.1610602114] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The comparative study of cell types is a powerful approach toward deciphering animal evolution. To avoid selection biases, however, comparisons ideally involve all cell types present in a multicellular organism. Here, we use image registration and a newly developed "Profiling by Signal Probability Mapping" algorithm to generate a cellular resolution 3D expression atlas for an entire animal. We investigate three-segmented young worms of the marine annelid Platynereis dumerilii, with a rich diversity of differentiated cells present in relatively low number. Starting from whole-mount expression images for close to 100 neural specification and differentiation genes, our atlas identifies and molecularly characterizes 605 bilateral pairs of neurons at specific locations in the ventral nerve cord. Among these pairs, we identify sets of neurons expressing similar combinations of transcription factors, located at spatially coherent anterior-posterior, dorsal-ventral, and medial-lateral coordinates that we interpret as cell types. Comparison with motor and interneuron types in the vertebrate neural tube indicates conserved combinations, for example, of cell types cospecified by Gata1/2/3 and Tal transcription factors. These include V2b interneurons and the central spinal fluid-contacting Kolmer-Agduhr cells in the vertebrates, and several neuron types in the intermediate ventral ganglionic mass in the annelid. We propose that Kolmer-Agduhr cell-like mechanosensory neurons formed part of the mucociliary sole in protostome-deuterostome ancestors and diversified independently into several neuron types in annelid and vertebrate descendants.
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37
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Salas P, Vinaithirthan V, Newman-Smith E, Kourakis MJ, Smith WC. Photoreceptor specialization and the visuomotor repertoire of the primitive chordate Ciona. J Exp Biol 2018; 221:jeb177972. [PMID: 29511068 PMCID: PMC5963834 DOI: 10.1242/jeb.177972] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 02/22/2018] [Indexed: 01/06/2023]
Abstract
The swimming tadpole larva of Ciona has one of the simplest central nervous systems (CNSs) known, with only 177 neurons. Despite its simplicity, the Ciona CNS has a common structure with the CNS of its close chordate relatives, the vertebrates. The recent completion of a larval Ciona CNS connectome creates enormous potential for detailed understanding of chordate CNS function, yet our understanding of Ciona larval behavior is incomplete. We show here that Ciona larvae have a surprisingly rich and dynamic set of visual responses, including a looming-object escape behavior characterized by erratic circular swims, as well as negative phototaxis characterized by sustained directional swims. Making use of mutant lines, we show that these two behaviors are mediated by distinct groups of photoreceptors. The Ciona connectome predicts that these two behavioral responses should act through distinct, but overlapping, visuomotor pathways, and that the escape behavior is likely to be integrated into a broader startle behavior.
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Affiliation(s)
- Priscilla Salas
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Vall Vinaithirthan
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Erin Newman-Smith
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Matthew J Kourakis
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - William C Smith
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
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38
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Abstract
The brain is a network of neurons, one that generates behaviour, and knowing the former is crucial to understanding the latter. Identifying the exact network of synaptic connections, or connectome, of the fly's central nervous system is now a major objective in Drosophila neurobiology, one that has been initiated in several laboratories, especially the Janelia Research Campus of the Howard Hughes Medical Institute. Progress is most advanced in the optic neuropiles of the visual system. The effort to derive a connectome from these and other neuropile regions is proceeding by various methods of electron microscopy, especially focused-ion beam milling scanning electron microscopy, and relies upon - but is to be carefully distinguished from - published light microscopic methods that reveal the projections of genetically labelled cell types. The latter reveal those neurons that come into close proximity and are therefore candidate synaptic partners. Synaptic partnerships are not in fact reliably revealed by such candidate pairs, anatomical connections often revealing unexpected pathways. Synaptic partnerships identified from ultrastructural features provide a strong heuristic basis to interpret not only functional interactions between identified neurons, but also a powerful means to predict such interactions, and suggest functional pathways not readily predicted from existing experimental evidence. The analysis of circuit function may proceed cell by cell, by examining the behavioural outcome of either interrupting or restoring function to any one element in an anatomically defined circuit, but can be foiled by degeneracy in pathway elements. Circuit information can also be used to identify and analyse circuit motifs, and their role in higher-order network properties. These attempts in Drosophila anticipate parallel attempts in other systems, notably the inner plexiform layer of the vertebrate retina, and augment the one complete connectome already available to us, that available for 30 years in the nematode Caenorhabditis elegans.
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Affiliation(s)
- Ian A Meinertzhagen
- a Department of Psychology and Neuroscience, Life Sciences Centre , Dalhousie University , Halifax , Canada ;,b Janelia Research Campus of Howard Hughes Medical Institute , Ashburn , VA , USA
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39
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Williams EA, Verasztó C, Jasek S, Conzelmann M, Shahidi R, Bauknecht P, Mirabeau O, Jékely G. Synaptic and peptidergic connectome of a neurosecretory center in the annelid brain. eLife 2017; 6:26349. [PMID: 29199953 PMCID: PMC5747525 DOI: 10.7554/elife.26349] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 12/02/2017] [Indexed: 12/15/2022] Open
Abstract
Neurosecretory centers in animal brains use peptidergic signaling to influence physiology and behavior. Understanding neurosecretory center function requires mapping cell types, synapses, and peptidergic networks. Here we use transmission electron microscopy and gene expression mapping to analyze the synaptic and peptidergic connectome of an entire neurosecretory center. We reconstructed 78 neurosecretory neurons and mapped their synaptic connectivity in the brain of larval Platynereis dumerilii, a marine annelid. These neurons form an anterior neurosecretory center expressing many neuropeptides, including hypothalamic peptide orthologs and their receptors. Analysis of peptide-receptor pairs in spatially mapped single-cell transcriptome data revealed sparsely connected networks linking specific neuronal subsets. We experimentally analyzed one peptide-receptor pair and found that a neuropeptide can couple neurosecretory and synaptic brain signaling. Our study uncovered extensive networks of peptidergic signaling within a neurosecretory center and its connection to the synaptic brain.
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Affiliation(s)
| | - Csaba Verasztó
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Sanja Jasek
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | | | - Réza Shahidi
- Max Planck Institute for Developmental Biology, Tübingen, Germany.,Living Systems Institute, University of Exeter, Exeter, United Kingdom
| | | | - Olivier Mirabeau
- Genetics and Biology of Cancers Unit, Institut Curie, INSERM U830, Paris Sciences et Lettres Research University, Paris, France
| | - Gáspár Jékely
- Max Planck Institute for Developmental Biology, Tübingen, Germany.,Living Systems Institute, University of Exeter, Exeter, United Kingdom
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40
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Schlegel P, Costa M, Jefferis GS. Learning from connectomics on the fly. CURRENT OPINION IN INSECT SCIENCE 2017; 24:96-105. [PMID: 29208230 DOI: 10.1016/j.cois.2017.09.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 09/18/2017] [Accepted: 09/19/2017] [Indexed: 06/07/2023]
Abstract
Parallels between invertebrates and vertebrates in nervous system development, organisation and circuits are powerful reasons to use insects to study the mechanistic basis of behaviour. The last few years have seen the generation in Drosophila melanogaster of very large light microscopy data sets, genetic driver lines and tools to report or manipulate neural activity. These resources in conjunction with computational tools are enabling large scale characterisation of neuronal types and their functional properties. These are complemented by 3D electron microscopy, providing synaptic resolution data. A whole brain connectome of the fly larva is approaching completion based on manual reconstruction of electron-microscopy data. An adult whole brain dataset is already publicly available and focussed reconstruction is under way, but its 40× greater volume would require ∼500-5000 person-years of manual labour. Nevertheless rapid technical improvements in imaging and especially automated segmentation will likely deliver a complete adult connectome in the next 5 years. To enhance our understanding of the circuit basis of behaviour, light and electron microscopy outputs must be integrated with functional and physiological information into comprehensive databases. We review presently available data, tools and opportunities in Drosophila. We then consider the limits and potential of future progress and how this may impact neuroscience in rich model systems provided by larger insects and vertebrates.
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Affiliation(s)
- Philipp Schlegel
- Drosophila Connectomics Group, Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Marta Costa
- Drosophila Connectomics Group, Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
| | - Gregory Sxe Jefferis
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK; Drosophila Connectomics Group, Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
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41
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Carrillo-Baltodano AM, Meyer NP. Decoupling brain from nerve cord development in the annelid Capitella teleta: Insights into the evolution of nervous systems. Dev Biol 2017; 431:134-144. [DOI: 10.1016/j.ydbio.2017.09.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 09/17/2017] [Accepted: 09/17/2017] [Indexed: 10/18/2022]
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42
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Pipkin JE, Bushong EA, Ellisman MH, Kristan WB. Patterns and distribution of presynaptic and postsynaptic elements within serial electron microscopic reconstructions of neuronal arbors from the medicinal leech Hirudo verbana. J Comp Neurol 2017; 524:3677-3695. [PMID: 27636374 DOI: 10.1002/cne.24120] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 06/15/2016] [Accepted: 09/10/2016] [Indexed: 12/11/2022]
Abstract
Microscale connectomics involves the large-scale acquisition of high-resolution serial electron micrographs from which neuronal arbors can be reconstructed and synapses can be detected. In addition to connectivity information, these data sets are also rich with structural information, including vesicle types, number of postsynaptic partners at a given presynaptic site, and spatial distribution of synaptic inputs and outputs. This study uses serial block-face scanning electron microscopy (EM) to collect two volumes of serial EM data from ganglia of the medicinal leech. For the first volume, we sampled a small fraction of the neuropil belonging to an adult ganglion. From this data set we measured the proportion of arbors that contained vesicles and the types of vesicles contained and developed criteria to identify synapses and to measure the number of apparent postsynaptic partners in apposition to presynaptic boutons. For the second data set, we sampled an entire juvenile ganglion, which included the somata and arbors of all the neurons. We used this data set to placd our findings from mature tissue in the context of fully reconstructed arbors and to explore the spatial distribution of synaptic inputs and outputs on these arbors. We observed that some neurons segregated their arbors into input only and mixed input/output zones, that other neurons contained exclusively mixed input/output zones, and that still others contained only input zones. These results provide the groundwork for future behavioral studies. J. Comp. Neurol. 524:3677-3695, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Jason E Pipkin
- Neurosciences Graduate Program, University of California at San Diego, La Jolla, California, 92093. .,Neurobiology Section, Division of Biological Sciences, University of California at San Diego, La Jolla, California, 92093.
| | - Eric A Bushong
- National Center for Microscopy and Imaging Research, University of California at San Diego, La Jolla, California, 92093
| | - Mark H Ellisman
- National Center for Microscopy and Imaging Research, University of California at San Diego, La Jolla, California, 92093.,Department of Neurosciences, University of California at San Diego School of Medicine, La Jolla, California, 92093
| | - William B Kristan
- Neurobiology Section, Division of Biological Sciences, University of California at San Diego, La Jolla, California, 92093
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43
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Kerbl A, Conzelmann M, Jékely G, Worsaae K. High diversity in neuropeptide immunoreactivity patterns among three closely related species of Dinophilidae (Annelida). J Comp Neurol 2017; 525:3596-3635. [PMID: 28744909 DOI: 10.1002/cne.24289] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 06/23/2017] [Accepted: 07/07/2017] [Indexed: 12/31/2022]
Abstract
Neuropeptides are conserved metazoan signaling molecules, and represent useful markers for comparative investigations on the morphology and function of the nervous system. However, little is known about the variation of neuropeptide expression patterns across closely related species in invertebrate groups other than insects. In this study, we compare the immunoreactivity patterns of 14 neuropeptides in three closely related microscopic dinophilid annelids (Dinophilus gyrociliatus, D. taeniatus and Trilobodrilus axi). The brains of all three species were found to consist of around 700 somata, surrounding a central neuropil with 3-5 ventral and 2-5 dorsal commissures. Neuropeptide immunoreactivity was detected in the brain, the ventral cords, stomatogastric nervous system, and additional nerves. Different neuropeptides are expressed in specific, non-overlapping cells in the brain in all three species. FMRFamide, MLD/pedal peptide, allatotropin, RNamide, excitatory peptide, and FVRIamide showed a broad localization within the brain, while calcitonin, SIFamide, vasotocin, RGWamide, DLamide, FLamide, FVamide, MIP, and serotonin were present in fewer cells in demarcated regions. The different markers did not reveal ganglionic subdivisions or physical compartmentalization in any of these microscopic brains. The non-overlapping expression of different neuropeptides may indicate that the regionalization in these uniform, small brains is realized by individual cells, rather than cell clusters, representing an alternative to the lobular organization observed in several macroscopic annelids. Furthermore, despite the similar gross brain morphology, we found an unexpectedly high variation in the expression patterns of neuropeptides across species. This suggests that neuropeptide expression evolves faster than morphology, representing a possible mechanism for the evolutionary divergence of behaviors.
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Affiliation(s)
- Alexandra Kerbl
- Marine Biological Section - Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | | | - Gáspár Jékely
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Katrine Worsaae
- Marine Biological Section - Department of Biology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
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Larderet I, Fritsch PM, Gendre N, Neagu-Maier GL, Fetter RD, Schneider-Mizell CM, Truman JW, Zlatic M, Cardona A, Sprecher SG. Organization of the Drosophila larval visual circuit. eLife 2017; 6:28387. [PMID: 30726702 PMCID: PMC5577918 DOI: 10.7554/elife.28387] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 08/07/2017] [Indexed: 11/20/2022] Open
Abstract
Visual systems transduce, process and transmit light-dependent environmental cues. Computation of visual features depends on photoreceptor neuron types (PR) present, organization of the eye and wiring of the underlying neural circuit. Here, we describe the circuit architecture of the visual system of Drosophila larvae by mapping the synaptic wiring diagram and neurotransmitters. By contacting different targets, the two larval PR-subtypes create two converging pathways potentially underlying the computation of ambient light intensity and temporal light changes already within this first visual processing center. Locally processed visual information then signals via dedicated projection interneurons to higher brain areas including the lateral horn and mushroom body. The stratified structure of the larval optic neuropil (LON) suggests common organizational principles with the adult fly and vertebrate visual systems. The complete synaptic wiring diagram of the LON paves the way to understanding how circuits with reduced numerical complexity control wide ranges of behaviors.
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Affiliation(s)
- Ivan Larderet
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | | | - Nanae Gendre
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | | | - Richard D Fetter
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | | | - James W Truman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Marta Zlatic
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Albert Cardona
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Simon G Sprecher
- Department of Biology, University of Fribourg, Fribourg, Switzerland
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Abstract
A map of a neuronal circuit in a marine worm reveals how simple networks of neurons can control behavior.
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Affiliation(s)
- Yee Lian Chew
- MRC Laboratory of Molecular Biology, University of Cambridge, Cambridge, United Kingdom
| | - William R Schafer
- MRC Laboratory of Molecular Biology, University of Cambridge, Cambridge, United Kingdom
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Shettigar N, Joshi A, Dalmeida R, Gopalkrishna R, Chakravarthy A, Patnaik S, Mathew M, Palakodeti D, Gulyani A. Hierarchies in light sensing and dynamic interactions between ocular and extraocular sensory networks in a flatworm. SCIENCE ADVANCES 2017; 3:e1603025. [PMID: 28782018 PMCID: PMC5533540 DOI: 10.1126/sciadv.1603025] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 06/27/2017] [Indexed: 05/23/2023]
Abstract
Light sensing has independently evolved multiple times under diverse selective pressures but has been examined only in a handful among the millions of light-responsive organisms. Unsurprisingly, mechanistic insights into how differential light processing can cause distinct behavioral outputs are limited. We show how an organism can achieve complex light processing with a simple "eye" while also having independent but mutually interacting light sensing networks. Although planarian flatworms lack wavelength-specific eye photoreceptors, a 25 nm change in light wavelength is sufficient to completely switch their phototactic behavior. Quantitative photoassays, eye-brain confocal imaging, and RNA interference/knockdown studies reveal that flatworms are able to compare small differences in the amounts of light absorbed at the eyes through a single eye opsin and convert them into binary behavioral outputs. Because planarians can fully regenerate, eye-brain injury-regeneration studies showed that this acute light intensity sensing and processing are layered on simple light detection. Unlike intact worms, partially regenerated animals with eyes can sense light but cannot sense finer gradients. Planarians also show a "reflex-like," eye-independent (extraocular/whole-body) response to low ultraviolet A light, apart from the "processive" eye-brain-mediated (ocular) response. Competition experiments between ocular and extraocular sensory systems reveal dynamic interchanging hierarchies. In intact worms, cerebral ocular response can override the reflex-like extraocular response. However, injury-regeneration again offers a time window wherein both responses coexist, but the dominance of the ocular response is reversed. Overall, we demonstrate acute light intensity-based behavioral switching and two evolutionarily distinct but interacting light sensing networks in a regenerating organism.
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Affiliation(s)
- Nishan Shettigar
- Institute for Stem Cell Biology and Regenerative Medicine (inStem), National Centre for Biological Sciences, GKVK Post, Bangalore 560065, India
- Shanmugha Arts, Science, Technology and Research Academy (SASTRA) University, Tirumalaisamudram, Thanjavur 613401, India
| | - Asawari Joshi
- Institute for Stem Cell Biology and Regenerative Medicine (inStem), National Centre for Biological Sciences, GKVK Post, Bangalore 560065, India
| | - Rimple Dalmeida
- Institute for Stem Cell Biology and Regenerative Medicine (inStem), National Centre for Biological Sciences, GKVK Post, Bangalore 560065, India
- Shanmugha Arts, Science, Technology and Research Academy (SASTRA) University, Tirumalaisamudram, Thanjavur 613401, India
| | - Rohini Gopalkrishna
- Institute for Stem Cell Biology and Regenerative Medicine (inStem), National Centre for Biological Sciences, GKVK Post, Bangalore 560065, India
| | - Anirudh Chakravarthy
- Institute for Stem Cell Biology and Regenerative Medicine (inStem), National Centre for Biological Sciences, GKVK Post, Bangalore 560065, India
| | - Siddharth Patnaik
- Institute for Stem Cell Biology and Regenerative Medicine (inStem), National Centre for Biological Sciences, GKVK Post, Bangalore 560065, India
| | - Manoj Mathew
- National Centre for Biological Sciences, GKVK Post, Bangalore 560065, India
| | - Dasaradhi Palakodeti
- Institute for Stem Cell Biology and Regenerative Medicine (inStem), National Centre for Biological Sciences, GKVK Post, Bangalore 560065, India
| | - Akash Gulyani
- Institute for Stem Cell Biology and Regenerative Medicine (inStem), National Centre for Biological Sciences, GKVK Post, Bangalore 560065, India
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47
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Tsukamoto H, Chen IS, Kubo Y, Furutani Y. A ciliary opsin in the brain of a marine annelid zooplankton is ultraviolet-sensitive, and the sensitivity is tuned by a single amino acid residue. J Biol Chem 2017. [PMID: 28623234 DOI: 10.1074/jbc.m117.793539] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ciliary opsins were classically thought to function only in vertebrates for vision, but they have also been identified recently in invertebrates for non-visual photoreception. Larvae of the annelid Platynereis dumerilii are used as a zooplankton model, and this zooplankton species possesses a "vertebrate-type" ciliary opsin (named c-opsin) in the brain. Platynereis c-opsin is suggested to relay light signals for melatonin production and circadian behaviors. Thus, the spectral and biochemical characteristics of this c-opsin would be directly related to non-visual photoreception in this zooplankton model. Here we demonstrate that the c-opsin can sense UV to activate intracellular signaling cascades and that it can directly bind exogenous all-trans-retinal. These results suggest that this c-opsin regulates circadian signaling in a UV-dependent manner and that it does not require a supply of 11-cis-retinal for photoreception. Avoidance of damaging UV irradiation is a major cause of large-scale daily zooplankton movement, and the observed capability of the c-opsin to transmit UV signals and bind all-trans-retinal is ideally suited for sensing UV radiation in the brain, which presumably lacks enzymes producing 11-cis-retinal. Mutagenesis analyses indicated that a unique amino acid residue (Lys-94) is responsible for c-opsin-mediated UV sensing in the Platynereis brain. We therefore propose that acquisition of the lysine residue in the c-opsin would be a critical event in the evolution of Platynereis to enable detection of ambient UV light. In summary, our findings indicate that the c-opsin possesses spectral and biochemical properties suitable for UV sensing by the zooplankton model.
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Affiliation(s)
- Hisao Tsukamoto
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, Okazaki 444-8585, Japan; Department of Structural Molecular Science, Graduate University for Advanced Studies, Hayama, Kanagawa 240-0193, Japan.
| | - I-Shan Chen
- Division of Biophysics and Neurobiology, Department of Molecular Physiology, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan; Physiological Sciences, SOKENDAI, Graduate University for Advanced Studies, Hayama, Kanagawa 240-0193, Japan
| | - Yoshihiro Kubo
- Division of Biophysics and Neurobiology, Department of Molecular Physiology, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan; Physiological Sciences, SOKENDAI, Graduate University for Advanced Studies, Hayama, Kanagawa 240-0193, Japan
| | - Yuji Furutani
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, Okazaki 444-8585, Japan; Department of Structural Molecular Science, Graduate University for Advanced Studies, Hayama, Kanagawa 240-0193, Japan
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48
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Starunov VV, Voronezhskaya EE, Nezlin LP. Development of the nervous system in Platynereis dumerilii (Nereididae, Annelida). Front Zool 2017; 14:27. [PMID: 28559917 PMCID: PMC5445494 DOI: 10.1186/s12983-017-0211-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 05/09/2017] [Indexed: 12/14/2022] Open
Abstract
Background The structure and development of the nervous system in Lophotrochozoa has long been recognized as one of the most important subjects for phylogenetic and evolutionary discussion. Many recent papers have presented comprehensive data on the structure and development of catecholaminergic, serotonergic and FMRFamidergic parts of the nervous system. However, relatively few papers contain detailed descriptions of the nervous system in Annelida, one of the largest taxa of Lophotrochozoa. The polychaete species Platynereis dumerilii has recently become one of the more popular model animals in evolutionary and developmental biology. The goal of the present study was to provide a detailed description of its neuronal development. The data obtained will contribute to a better understanding of the basic features of neuronal development in polychaetes. Results We have studied the development of the nervous system in P. dumerilii utilizing histo- and immunochemical labelling of catecholamines, serotonin, FMRFamide related peptides, and acetylated tubulin. The first neuron differentiates at the posterior extremity of the protrochophore, reacts to the antibodies against both serotonin and FMRFamide. Then its fibres run forwards along the ventral side. Soon, more neurons appear at the apical extreme, and their basal neurites form the basel structure of the developing brain (cerebral neuropil and circumesophageal connectives). Initial development of the nervous system starts in two rudiments: anterior and posterior. At the nectochaete stage, segmental ganglia start to differentiate in the anterior-to-posterior direction, and the first structures of the stomatogastric and peripheral nervous system appear. All connectives including the unpaired ventral cord develop from initially paired nerves. Conclusions We present a detailed description of Platynereis dumerilii neuronal development based on anti-acetylated tubulin, serotonin, and FMRFamide-like immunostaining as well as catecholamine histofluorescence. The development of the nervous system starts from peripheral pioneer neurons at both the posterior and anterior poles of the larva, and their neurites form a scaffold upon which the adult central nervous system develops. The anterior-to-posterior mode of the ventral ganglia development challenges the primary heteronomy concept. Comparison with the development of Mollusca reveals substantial similarities with early neuronal development in larval Solenogastres. Electronic supplementary material The online version of this article (doi:10.1186/s12983-017-0211-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Viktor V Starunov
- Department of Invertebrate Zoology, St-Petersburg State University, St-Petersburg, 199034 Russia.,Zoological Institute Rus, Acad. Sci, St-Petersburg, 199034 Russia
| | | | - Leonid P Nezlin
- Institute of Developmental Biology, Rus. Acad. Sci, Moscow, 119991 Russia
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49
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Hildebrand DGC, Cicconet M, Torres RM, Choi W, Quan TM, Moon J, Wetzel AW, Scott Champion A, Graham BJ, Randlett O, Plummer GS, Portugues R, Bianco IH, Saalfeld S, Baden AD, Lillaney K, Burns R, Vogelstein JT, Schier AF, Lee WCA, Jeong WK, Lichtman JW, Engert F. Whole-brain serial-section electron microscopy in larval zebrafish. Nature 2017; 545:345-349. [PMID: 28489821 PMCID: PMC5594570 DOI: 10.1038/nature22356] [Citation(s) in RCA: 176] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 04/11/2017] [Indexed: 12/18/2022]
Abstract
High-resolution serial-section electron microscopy (ssEM) makes it possible to investigate the dense meshwork of axons, dendrites, and synapses that form neuronal circuits. However, the imaging scale required to comprehensively reconstruct these structures is more than ten orders of magnitude smaller than the spatial extents occupied by networks of interconnected neurons, some of which span nearly the entire brain. Difficulties in generating and handling data for large volumes at nanoscale resolution have thus restricted vertebrate studies to fragments of circuits. These efforts were recently transformed by advances in computing, sample handling, and imaging techniques, but high-resolution examination of entire brains remains a challenge. Here, we present ssEM data for the complete brain of a larval zebrafish (Danio rerio) at 5.5 days post-fertilization. Our approach utilizes multiple rounds of targeted imaging at different scales to reduce acquisition time and data management requirements. The resulting dataset can be analysed to reconstruct neuronal processes, permitting us to survey all myelinated axons (the projectome). These reconstructions enable precise investigations of neuronal morphology, which reveal remarkable bilateral symmetry in myelinated reticulospinal and lateral line afferent axons. We further set the stage for whole-brain structure-function comparisons by co-registering functional reference atlases and in vivo two-photon fluorescence microscopy data from the same specimen. All obtained images and reconstructions are provided as an open-access resource.
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Affiliation(s)
- David Grant Colburn Hildebrand
- Graduate Program in Neuroscience, Division of Medical Sciences, Graduate School of Arts and Sciences, Harvard University, Cambridge, Massachusetts, USA
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
- Center for Brain Science, Harvard University, Cambridge, Massachusetts, USA
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA
- Image and Data Analysis Core, Harvard Medical School, Boston, Massachusetts, USA
| | - Marcelo Cicconet
- Image and Data Analysis Core, Harvard Medical School, Boston, Massachusetts, USA
| | - Russel Miguel Torres
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Woohyuk Choi
- School of Electrical and Computer Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, South Korea
| | - Tran Minh Quan
- School of Electrical and Computer Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, South Korea
| | - Jungmin Moon
- School of Electrical and Computer Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, South Korea
| | - Arthur Willis Wetzel
- Pittsburgh Supercomputing Center, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | | | - Brett Jesse Graham
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Owen Randlett
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
| | - George Scott Plummer
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Ruben Portugues
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Isaac Henry Bianco
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Stephan Saalfeld
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
| | | | - Kunal Lillaney
- Department of Computer Science, Johns Hopkins University, Baltimore, Maryland, USA
| | - Randal Burns
- Department of Computer Science, Johns Hopkins University, Baltimore, Maryland, USA
| | - Joshua Tzvi Vogelstein
- Department of Biomedical Engineering and Institute for Computational Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Alexander Franz Schier
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
- Center for Brain Science, Harvard University, Cambridge, Massachusetts, USA
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
- Harvard Stem Cell Institute, Harvard University, Cambridge, Massachusetts, USA
- FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Wei-Chung Allen Lee
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Won-Ki Jeong
- School of Electrical and Computer Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, South Korea
| | - Jeff William Lichtman
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
- Center for Brain Science, Harvard University, Cambridge, Massachusetts, USA
| | - Florian Engert
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
- Center for Brain Science, Harvard University, Cambridge, Massachusetts, USA
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50
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Verasztó C, Ueda N, Bezares-Calderón LA, Panzera A, Williams EA, Shahidi R, Jékely G. Ciliomotor circuitry underlying whole-body coordination of ciliary activity in the Platynereis larva. eLife 2017; 6. [PMID: 28508746 PMCID: PMC5531833 DOI: 10.7554/elife.26000] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 05/14/2017] [Indexed: 01/23/2023] Open
Abstract
Ciliated surfaces harbouring synchronously beating cilia can generate fluid flow or drive locomotion. In ciliary swimmers, ciliary beating, arrests, and changes in beat frequency are often coordinated across extended or discontinuous surfaces. To understand how such coordination is achieved, we studied the ciliated larvae of Platynereis dumerilii, a marine annelid. Platynereis larvae have segmental multiciliated cells that regularly display spontaneous coordinated ciliary arrests. We used whole-body connectomics, activity imaging, transgenesis, and neuron ablation to characterize the ciliomotor circuitry. We identified cholinergic, serotonergic, and catecholaminergic ciliomotor neurons. The synchronous rhythmic activation of cholinergic cells drives the coordinated arrests of all cilia. The serotonergic cells are active when cilia are beating. Serotonin inhibits the cholinergic rhythm, and increases ciliary beat frequency. Based on their connectivity and alternating activity, the catecholaminergic cells may generate the rhythm. The ciliomotor circuitry thus constitutes a stop-and-go pacemaker system for the whole-body coordination of ciliary locomotion. DOI:http://dx.doi.org/10.7554/eLife.26000.001 The oceans contain a wide variety of microscopic organisms including bacteria, algae and animal larvae. Many of the microscopic animals that live in water use thousands of beating hair-like projections called cilia instead of muscles to swim around in the water. Understanding how these animals move will aid our understanding of how ocean processes, such as the daily migration of plankton to and from the surface of the water, are regulated. The larvae of a ragworm called Platynereis use cilia to move around. Like other animals, Platynereis has a nervous system containing neurons that form networks to control the body. It is possible that the nervous system is involved in coordinating the activity of the cilia to allow the larvae to manoeuvre in the water, but it was not clear how this could work. Here, Veraszto et al. investigated how Platynereis is able to swim. The experiments show that the larvae can coordinate their cilia so that they all stop beating at the same time and fold into to the body. Then the larvae can stimulate all of their cilia to resume beating. Veraszto et al. used a technique called electron microscopy to study how the nervous system connects to the cilia. This revealed that several giant neurons span the entire length of the larva and connect to cells that bear cilia. When these neurons were active, all the cilia in the body closed. When a different group of neurons in the larva was active, all of the cilia resumed beating. Together, these two groups of neurons were ultimately responsible for the swimming motions of the larvae. Together, the findings of Veraszto et al. show that a few neurons in the nervous system of the larvae provide a sophisticated system for controlling how the larvae swim around. This suggests that the microscopic animals found in marine environments are a lot more sophisticated than previously appreciated. A next challenge is to find out how the neurons that control cilia connect to the rest of the animal’s nervous system and how different cues influence when the larva swims or stops swimming. This would help us understand how the environment influences the distribution of animal larvae in the oceans and how this may change in the future. DOI:http://dx.doi.org/10.7554/eLife.26000.002
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Affiliation(s)
- Csaba Verasztó
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Nobuo Ueda
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | | | - Aurora Panzera
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | | | - Réza Shahidi
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Gáspár Jékely
- Max Planck Institute for Developmental Biology, Tübingen, Germany
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